Formation of the design model

Forming the design model was done by applying the existing guidelines and to fit them into the local conditions and the study aims. Figure 3 presents the simplified process of the final design.

There were five main aspects impacting to the final design. The process began from the theory which gives the base for the design frame. The next step was to apply the theory into the study; to recognize the limitations and the possibilities and the study aim. Questions like:

which parts can be applied and which are left out; what is relevant for achieving the aim, were to be answered.

The third step was already approved in the study area or through background studies

depending on the previous data available. However, the idea was to define the main features presented in the theory in relation to the study area. Through this, the general characteristics of the project farm environment could be recognized.

The next part was to describe the possibilities of the farm for the agroforestry system. This included the farmer’s (or farm manager’s) interview for figuring out their objectives, input possibilities and other desires.

The final part was to combine all the data collected and identify the farming possibilities. The final species selection and arrangement was limited to suitable agroforestry species and local environmental possibilities as well as farmer’s desires based on the data collected.

Main features Theory Applying the theory

into the study The outcome:

Farming possibilities Characteristics

of the target farm

Figure 3. Formation of the agroforestry design

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The idea is to create a frame that could be easy to modify into different cases. This was enabled by the design process moving from general to more focused case study. During this kind of a process, parts of the data collection and results can been dropped out if those are not found relevant for the case. However, the data collected should answer questions like: What are the main cultivation characteristics of the local environment? How does the target farm compensate with the surrounding environment? And, which of the results can be applied for the target farm?

4.1.2. Application of the design model to the case study

For this study the theory was taken from three existing guidelines: Altieri (1983), Nair (1989) and Jaenicke et al. (1995). Based on Altieri’s (1983) and Nair’s (1989) guidelines, the main features were selected to be ecological and social features of the study environment. More detailed elements were followed by all three guidelines.

Altieri’s (1983) guideline is a good base for all agroecosystem designs. In addition, of the Altieri's overall idea; “to see an agroecosystem as a part of natural functions”, some of his practical recommendations were applied to this study. Natural and primary productions were included by examining the native species in the existing farmland. This has been mentioned in Nair's (1989) guideline as well as a part of background information. As the study was carried out in the urban area of Harare, it was assumed that the most general descriptions of the farms (country, vegetation type, mean annual temperature, precipitation etc.) were equal.

Physiochemical factors like slope, water availability, basic nutrient content and pH were chosen to be determined in this study. These are mentioned in general in Altieri's (1983) guideline and more detailed in Nair's (1989) book. The basic nutrient content was primary macronutrients: nitrogen, phosphorus and potassium, as these nutrients are commonly most limiting factors in agricultural production (controls a process of growth, functioning etc.), and usually determined in agroecosystem analysis because of that. These nutrients are also

consumed most by plants (> 10 kg/ha) (Brady 1984). Secondary macronutrients, calcium and magnesium which agricultural plants usually take < 10kg/ha, were also chosen because these two macronutrients are usually part of this kind of basic agricultural soil analysis (Brady 1984, Viljavuuspalvelu 2008). The other parameters, pH-levels and texture tell about the

soil’s current fertility and functioning (Brady 1984, Viljavuuspalvelu 2008). PH-levels have strong effects on plant growth as its own, but the main impact comes through inorganic ions availability in different pH levels. In Jaenicke et al.’s research one of the criteria was related to soil acidity, so based on this pH was also natural choice for the study.

The need for socioeconomic studies was underlined in all three guidelines. These characteristics were to be measured mainly in the local farmers’ questionnaire or in the interview of the farm managers. For example, questions about labour intensity and cultivation target were included based on Nair’s and Jaenicke et al.’s recommendation. Part of the

questions were left out or modified mainly because of their unsuitability or sensitivity (for example land ownership or capital details).

One part of Nair's guideline is the evaluation of the system. This was left out because implementation of the design was unsure and the time for the study was not long enough for evaluation. Furthermore, Altieri have presented the need of description of farm management practises as part of the new design process, but for this study these details were not found essential because the project farm did not have any regulated cultivation. Jaenicke et al.’s guideline was used most in the data analysis process as their research offers important notes to be considered when choosing the species. Species growing characteristics, water and nutrient needs, and multipurpose values were for example included in the species selection part.

The application of the design model to the study is presented in the figure 4. The detailed list of the research variables are presented in Appendix (annex 1), under the headings of the local farmer’s questionnaire, the agroecological characters of the project farm and the interview of the project farm managers’.

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Figure 4. Formation of the agroforestry design applied to the case study Legend:

Theory Applying the theory

into the study The outcome:

Farming possibilities Characteristics

of the target area

Data collection

5 CASE STUDY

5.1 Materials